Potential of black pepper as a functional food for treatment of airways disorders

• Black pepper, a popular spice, has folkloric reputation for use in airway disorders.
• Black pepper and piperine relieved carbachol-induced bronchospasm in rats in vivo.
• Black pepper and piperine potentiated isoprenaline concentration-response curves and inhibited Ca2+ response-curves non-competitively.
• Black pepper was as potent as piperine in its bronchodilator action.
• Black pepper may be used as a functional food for treating bronchitis and asthma.

The potential of black pepper (Piper nigrum) to cause bronchodilation was examined using in vivo and in vitro assays. HPLC fingerprint analysis of the crude extract of Piper nigrum (Pn.Cr) and its fractions showed piperine, piperidine, eugenol and catechin as plant constituents. In anaesthetized rats, Pn.Cr and piperine relieved carbachol (CCh)-induced bronchospasm. In isolated guinea-pig trachea, Pn.Cr and piperine inhibited CCh and K+ (80 mM)-induced contractions, potentiated isoprenaline concentration–response curves (CRCs) and suppressed Ca2+ CRCs. In guinea-pig atria, Pn.Cr and piperine showed stimulatory and inhibitory effects on rate and force of contraction. Its fractions showed similar activities with varied potency in the in vivo and in vitro assays. These results suggest that black pepper and piperine cause bronchodilation through dual inhibition of phosphodiesterase enzyme and Ca2+ influx, which substantiate its potential as a functional food ingredient for airway disorders.